I included more instances of historic inhabited spacecraft than the original chart (above), as well as inhabited spacecraft that were docked to each other, combining their habitable volumes for a period of time (these include Apollo CM & LM, Apollo CM & Soyuz, Space Shuttle & Spacelab, Space Shuttle & Mir).

Some spacecraft (or variants of spacecraft) are listed more than once. This reflects either evolution in the design of the spacecraft (such as Soyuz) or different mission profiles (such as the three person Apollo 8 circumlunar mission with only the Command Module, versus the Apollo 17 mission in which one crew member was aboard the Apollo CM for ~12 days while the other two crew members were on the Lunar surface with their LM). Also reflected is the difference between the time spent within the reentry capable portion of a spacecraft versus its entire habitable volume (Soyuz, Shenzhou) for a duration of less than a day.

Using linear extrapolation (solid grey line) of this relationship between spacecraft volume per person and maximum mission duration, we can see the desired volumes required for missions of longer duration if current volume/duration ratios are continued. Also on this chart are the planned volume per person values for two Bigelow Aerospace habitat modules, the BA 330, and the BA 2100 (Olympus) *pdf. Following the current trend in volume versus mission length, a single BA 330 could provide volume for a six person crew for a mission duration of just under half a year, whereas a single BA 2100 could be home to a crew of 16 for a year. Combinations of these expandable modules could accommodate even more crew members, or enable even longer missions.

Bigelow Aerospace is currently testing the BEAM (Bigelow Expandable Activity Module) on board the International Space Station (it contributes 16 cubic meters to the station’s volume while attached), and hopes to further test their technologies in partnership with NASA and ULA.

The data was gathered from a variety of online sources, largely from Wikipedia and Encyclopedia Astronautica and is therefore subject to the accuracy of those sources.